Hydrofoil surfcraft

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It’s always hard to get a good shot underwater, with the breather I can position myself and the camera constantly 2 or 3 feet underwater waiting for the wave and rider to arrive,
It’d also be good for boat maintenance, scrounging along a reef, goofing off in a pool, whatevs.
It’s like shallow water scuba for pennies.

You don’t have to come up to the surface to breath and clearing the snorkel was always a pain if you didn’t get it right first go. You may as well spit it out, drain the snorkel and start again but now you don’t have to.
It’s cool just to lurk fully submerged as part of the scenery.
I’ll pretty it up and show how it works.

When we were kids (55 years ago), we had some snorkels that had a cylindrical cage at the surface end. The top of the snorkel tube was curved down. In the cylindrical cage at the bottom of the curved top tube, there was a ping pong ball. When you went under, the ping pong ball would rise and block the snorkel air intake — to stop water from filling the snorkel.

Back to the foils. The surfcraft needed isn’t hard to work out, the foil design isn’t difficult but the connection between craft and foil is the conundrum.
And it’s only the connection of mast to craft that’s. A worry because we’re riding a glass skinned block of foam. Unless you’re riding a wood board then basic screws will do fine, but for glass craft it’s all about resin and that involves skill and patience and making a mast that fits into the volume of the spcraft be it a Tuttle box or FCS plugs.
In the end all the variations are complex until I thought of using double sided tape that 3M make. It’s the same stuff GoPro use for their board mounts and luckily for me I use multiple masts/struts so I can spread out the forces likely to rip the foil off the board. I rang 3M and they sent over some samples to test, some of them have a 10 year marine guarantee.
So now I had a new system to attach foil to board but I needed to make custom struts to use the 3M tape.
The tape works best on hi energy surfaces like polycarbonate and I’ve got sheets of that in clear 6mm. It’s the stuff they use as bank security screens, it’s hard to scratch, almost unbreakable and clear so you look like you’re flying over the water. Colours are OK but clears the best.

I needed to make from the polycarbonate a footing to be adhered to the hull of the craft , a vertical section and a footing to connect to the foil. The simplest way would be to thermoform single pieces of polycarbonate and stick one end to the board and the other end to the foil.
Grab a heat gun and some polypropylene for testing and cut out struts.
Place one end in a vice with smooth aluminium angle so as to not wreck the plastic in the jaws of the vice.
I also rounded the aluminium angle to get a smooth rounded bend.

Heat the line of the bend, fold over with a smooth piece of wood and clamp into position. When cooled, it doesn’t spring back so you get a true 90 bend every time.

The struts are permanently affixed to the board but that’s not a big deal if you have a few spare around the house.
The struts flex and I think of them as shock absorbers, rather than jumping and twitching at every ripple and power surge, the flexible struts smooth out the ride.

Bret, I see black, blue and white struts. Looks like you’ve made quite a few but no clear ones? Also do you find any speed difference between the variable lift versions shown before versus the constant lift shown in the last two pictures?

All the best

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Personally I'm always ready to learn, although I do not always like being taught. - Winston Churchill

Greg, I’ve made clear ones but they don’t photograph well. But I’ll do some new ones.
I don’t think there’s a speed difference but there’s a control difference. The single foils are all lift all the time so they need to be the right size/ area for a certain wave size. The split foils can vary the lift as they speed up so they cover a wider range of waves and speeds.
Red boards, thanks for the props, I’m all over the place with lots of inventions on the go.
I just round the leading and trailing edges of the struts and leave it at that unless you think there’s a benefit to be had with more foiling ?